Cardiovascular Effects of Hind-limb Unweighing in Mice / 대한마취과학회지
Korean Journal of Anesthesiology
;
: 222-228, 2007.
Article
in Korean
| WPRIM
| ID: wpr-159523
ABSTRACT
BACKGROUND:
Orthostatic intolerance is a debilitating problem that can occur after prolonged bed-rest, exposure to microgravity, and in the elderly. This study examined the integrated cardiovascular response to baroreceptor activation in a hind-limb unweighing (HLU) mouse model of microgravity to test the hypothesis that both the pressor and contractility response are attenuated in HLU mice.METHODS:
C57BL/6 mice (25-30 g body wt, 8-10 wk old) were exposed to HLU for 2 weeks. A bilateral carotid artery occlusion and open-loop baroreceptor stimulus was performed to measure the myocardial contractile responses using a left ventricular micromanometer-conductance catheter in the mice. In isolated myocytes simultaneous sarcomere shortening and calcium transient were measured in response to increasing concentrations of the beta-agonist isoproterenol.RESULTS:
In the controls, bilateral carotid artery occlusion increased the heart rate and mean arterial pressure. These responses were markedly attenuated in the HLU mice. A bilateral carotid artery occlusion also increased the slope of the end-systolic pressure volume relationship (Ees) by 70 +/- 11% and the slope was markedly attenuated to 10 +/- 8% in the HLU mice. Isoproterenol increased the sarcomere shortening in both control and HLU mice in a dose-dependent manner. However the contractile response to isoproterenol was significantly attenuated in the HLU mice than the controls.CONCLUSIONS:
Both the pressor and myocardial contractile responses appear to be impaired in a mouse model of microgravity.
Full text:
Available
Index:
WPRIM (Western Pacific)
Main subject:
Pressoreceptors
/
Sarcomeres
/
Weightlessness
/
Carotid Arteries
/
Calcium
/
Baroreflex
/
Muscle Cells
/
Orthostatic Intolerance
/
Catheters
/
Arterial Pressure
Type of study:
Prognostic study
Limits:
Animals
/
Humans
Language:
Korean
Journal:
Korean Journal of Anesthesiology
Year:
2007
Type:
Article
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